Rolling-mill



L. WOLFFGRAM.

ROLLING. MILL.

APPLICATION FILED JAN. 23| i919. 1,352,493.

Patented Sept. 14, 1920.

2 SHEETS-SHEET I.

sraies PATENT" OFFICE.

LUDWIG WOLFFGRAM, 0F ERIE, PENNSYLVANIA.

l ROLLING-MILL.

speeiiicauon of Lettersratent.

Patented Sept. 14, 1920.

Application led January 23, 1919.' Serial No. 272,642.

To all whom t may concern:

Be it known that I, LUDWIG WoLrFoiiAM, a citizen of Germany, and resident of Erie, countyof Erie, and State of Pennsylvania, liave invented certain new and useful Improvenients in Rolling-Mills, of which the following is a specification.

The present invention relates to improvements in rolling mills, and particularly for the manufacture of pipes, tubes oi' the like, an object of the invention being to provide such a device by means of which the pipes may be formed in a .relatively perfect manner, the pipe formed according to my vention being of uniform cross section throughout and perfectly round. To this end I propose to provide a series of reducing rolls so formed and arranged that the greatest working effect may be obtained there# from with less wear and with better results than has been possible with the previously known types of rolling mills.

With these and other objects in view an embodiment 'of my invention is shown in the accompanying drawings and this embodiment will be hereinafter more fully described with reference thereto and the invention will be finally pointed out in the claims.

In the accompanying drawings, y Figure 1 is a diagrammatic view showing the method of reducing the pipe and showino' the successive outlines of the periphery;

Fig. 2 is an elevation of a pair of reducing rolls according tok my invention;

Fig. 3 is a similar view of a succeeding pair of rolls;

Fig. 4 is a longitudinal sectional view through the line 4 4- Figs. 2 and 3; and

Fig.' 5 is an elevation ofthe final pair of reducing rolls. Similar reference characters indicate coi"- responding parts throughout the several figures of the drawings. U l

Referring to the drawings, a longitudinal core or mandrel rod 10 h/as disposed Ain spaced relation along the same a plurality of pairs of opposed and coperating rolls, the present embodiment showing six pairs: 11, 12; 13, 14; 15, 16; 17, 18; 19, 20; and 21, 22. The number of the pairs of. rolls, however, is immaterial as far as the invenhaving a smaller tion is concerned and for certain kinds of Work a dgreater or less number may be employed epending upon the diameter of the pipe, the hardness of the metal, etc.

The central'axes of all of the rolls, that is, their axes of rotation are in vertical planes at right angles to a vertical longitudinal plane through the axis of the mandrel rod 10, the axes of the opposed rolls being in the same vertical planes. The central planes of rotation as c-d and e-f Figs. 2 and 3, pass through the axis of the rod 10, but are inclined to the vertical line a-b indicating the vertical plane passing through the axis of the rod 10, so that the planes c-d and e-f and also the bases 113.12, i3, 14a, 15a', 163,173 is, i9, 20a, 21a and 22a of the grooves of the rolls form angles with the line 1f-b, While the,parallel axes of rotation of the rolls areinclined relativel to the horizontal plane g-i. the interme iate planes j and c-Z passing through the axis of the rod 1() and the points of contact of the opposed rolls, forming acute angles y with the horizontal plane g-i.

The adjacent pairs of rolls have their planes of rotation passing at opposite sides of the vertical plane 1f-b above and below the axis of the rod 10, and consequently the points of contact of the rolls of one pair are oifset from the points of contact of the Asucceeding pairs as indicated by the lines i-j and c Z, the ycontacting points of alternate pairs being in coincident planes.

The several pairs of rolls are thus disposed apart from one another and arran ed. in succession, alternate pairs of rolls being inclined at acuteangles to the intermediate pairs of rolls, and ing parallel with each other. n

The passes of the pairs of rolls, except the last or completion pair 21, 22 which is circular, are ,in the shape of circles extended along the axes 1-j and c-Z into triangular shaped extensions, which for the purpose of description rma be called excess portions. This shape is und by describing a circle diameter than the distance between the extremities of the grooves of the rolls and drawing tangents from said extremities to the circle. The pass of the rolls 13, 14. is smaller than that of the rolls 11, 12 while thc pass of the rolls 15, 16 is smaller than that of the rolls 13, 14 and similarly the pass of the rolls 17 18 is smaller than that of the rolls 15, 16. The pass of the rolls 19, 2O has its circular portion of the same radius as the circular portion of the rolls 17, 18 but the excess portion is of reduced size, the grooves of these rolls being less in width than those of the said rolls 17, 18. The iial or completion rolls 21, 22 have a circular pass, having the same diaineter as the circular portions of the rolls 17, 18 and 19, 20, this circular pass of'the said rolls 21, 22. corresponding to the desired completion shape of the type of tube to be formed.

The ingot 23 to be formed into pipe 1s of cylindrical form and is pushed along the mandrel rod by any suitable and usual means. The rolls are rotated by any suitable mechanism in the direction of movement of the ingot and the successivepairs of rolls beginning with 11, 12 are driven at radually increasing speed to compensate. or the increasing length of the ingot as it is reduced in its progress through the rolls, that is, the speed of the rolls 13, 14 is at least equal to the speed of the rolls 11, 12 plus the advancing speed of the ingot, the speed of the rolls 15, 16 is at least equal to the speed of the rolls 13, 14 plus the advancing speed of the ingot, a similar speed relation existing between the succeeding rolls so that the last pair of rolls have the greatest speed. The operation of my improved rolling mill is as follows:

As the ingot is pressed between the rolls 11 and 12 it will take the cross section of the space between the surface of the grooves and the mandrel rod 10 as shown in Fig. 2, being pressed into the excess portions of the pass as shown by the shaded parts 24, 25, 26 and 27, 28, 29 Fig. 1, the point of entrance between the rolls being indicated at 30 while the point of departure is indicated at 31. As the ingot passes between the next pair of rolls 13, 14 the accumulated or excess material 24, 25, 26 and 27, 28, 29 is rolled down by the rounded and the adjacent tangential portions indicated at 32a to 32 to 34 and 35 to 36 to 37, these portions being at one side of the opposed rolls and opposed to each other. These portions of the rolls are of greater circumference and working surface and are rotated at relatively greater speed, so that at these portions of the rolls the greatest working effect is obtained with the least amount of wear, and the reduction is substantially proportioned to the working effect of the rolls. At the same time the reduced diameter of the pass causes the pipe to be reduced in diameter. The excess portions of the rolls 13, 14 is indicated at 32,

33, 34 and 35, 36, 37 Fig. 1. -The excess accumulation produced by the rolls 13, 14 is rolled away by the rolls 15, 1G, the pipe at the same time being reduced and the accumulation taking the position indicated at 38, 39, 40 and 41, 42, 43 Fig. 1. A similar reductionbccurs between the rolls 17, 18, the excess accumulation being indicated at 44 45, 4e and 17,- 18,49 Fig. 1.

The rolls 19, 2O reduce the accumulation without reducing the diameter of the pipe, accumulation between these rolls 19, 2() being indicated at 50, 51, 52 and 53, 54, 55 Fig. 1, while the final rolls 21,22 which have a circular pass, roll away this accumulation, equalizing the thickness of the pipe at all points, the finished pipe passing from between the said rolls 21, 22 being perfectly round, smooth and of uniform thickness.

According to'my invention, a perfect pipe or tube may be formed in less time and with the least amount of wear upon the working parts. The working surfaces of the material are so disposed and arranged that the working effect is proportionate to the thickness of the material being worked upon so that the Greatest possible eiciency is oftained and the molecular structure of the metal is uniform at all points so that the intilshed pipe is of equal strength throughou I have illustrated and described a preferred and satisfactory embodiment of my invention but it is obvious that changes may be made therein within the spirit and scope thereof as defined in the appended claims.

I claim:

1. A rolling mill comprising a series of pairs of grooved rolls spaced apart and arranged in succession, the rolls of each pair being parallel and alternate airs of rolls being disposed at acute ang es to the intermediate pairs of rolls; the passes of the rolls of successive pairs being in arcs reduced in succession and having triangular extensions reduced in succession.

2. A rolling mill 'comprising a series of pairs of grooved rolls spaced apart and arranged in succession, the rolls of each pair being parallel and alternate pairs of rolls being disposed at acute angles to the intermediate pairs of rolls; the passes of the rolls of successive pairs being in arcs reduced in succession and having triangular extensions reduced in succession, and a succeeding pair of rolls having its pass in arcs the same as the preceding set of rolls with reduced triangular extensions.

3. A rolling mill comprising a series of pairs of grooved rolls spaced apart and arranged in succession, the rolls of each pair being arallel and alternate pairs of rolls being isposed at acute angles to the intermediate pairs of rolls; the passes of the rolls `of successive pairs being in arcs reduced in succession and having triangular pair of rolls. extensions reduced in succession, a succeeding pair of rolls having its pass in arcs the same as the preceding set or rolls and with reduced triangular extensions, and a final pair of rolls having a circular pass of the same diameter as the pass of the preceding In testimon that I claim the foregoing l0 as my invention, I have :signedl my name hereunder.

LUDWIG WOLFFGRAM., 

